Apparatus for drawing sheet glass



Sept. 22, 1925.

H. K. HITCHCOCK APPARATUS FOR DRAWING SHEET GLASS Filed Oct. 11, 1922 8 Sheets-Sheet 1 wvewraxa FIE-Z- Sept. 22, 1925.

H. K. HITCHCOCK APPARATUS FOR DRAWING SHEET GLASS Filed Oct. 11 1922 8 Sheets-Sheet 2 Sept. 22, 1925. 4

H. K. HITCl' iCOCK APPARATUS FOR DRAWING SHEET GLASS 8 Sheets-Sheet 3 Filed Opt. 11, 1922 ilililffiillil1:11---.

I I, l/YVENTOR .iii. -hiLziw Sept. 22, 1925.

H. K. HITCHCOCK APPARATUS FOR DRAWING SHEET GLASS Filed Oct. 11, 1922 8 Sheets-Sheet.

FIEJS- /M/NTOR Sept. 22, 1925.

H. K. HITCHCOCK APPARATUS FOR DRAWING SHEET GLASS 8 sheeis-sheet 5 Filed Oct. 11, 1922 FIBJD.

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Filed Oct. 11. 1922 8 Sheets-Sheet 6 Sept. 22, 1925.

H. K. HITCHCOCK APPARATUS FOR DRAWING SHEET GLASS 8 Sheets-Sheet 7 Filed Oct. 11, 1922 Eg E ILVVEIIYTOR q KJW Sept. 22, 1925.

H. K. HITCHCOCK APPARATUS FOR DRAWING SHEET GLASS 8' Sheets-Sheet 8 (Filed 0st. 11, 1922' /Akvs/ rb #414 We $46. I r

Patented Sept. 22, 1925.

v UNITED STATES PATENT O FF [C E HALBERT K. HITCHCOCK, OLE PITTSBURGH, PENNSYLVANIA, ASSIGNOR OF ONE-HALF TO HITCHCOCK EXPERIMENT COMPANY, A CORPORATION OF NEW' JERSEY;

APPARATUS FOR DRAWING SHEET GLASS.

Application filed October 11, 1922. Serial No. 593,719.

To all whom it may concern:

Be it known that I, HALBERT K. HITCH- ooon, a citizen of the United States, and a resident of Pittsburgh, in the county of: Allegheny and State of Pennsylvania, have made a new and useful invention in Improvements in Apparatus for Drawing Sheet Glass, of which the following is a specification.

The invention relates to apparatus for drawing sheet glass, which apparatus is illustrated in the present application, and, in

a general way, in my pending application Serial No. 53,212, as applied to the drawing of glass vertically through a preliminary annealing or tempering chamber, but it will be obvious that the device is not limited to use in such connection or in such position, and might even be used without the annealing chamber or for drawing glass in some direction other than vertical, such for instance as horizontal. The invention has for some of its principal objects the provision of an improved drawing device (1) which will insure the cooling of the sheet at a proper rate of speed, and one which may be controlled and speeded up as the cooling progresses, (2) which permits the cutting of the glass intermediate the ends of the drawing belts, thus reducing the danger of breakage, and minimizing the damage in case breaks occur while the glass is in progress through the device, which provides "for gripping the glass along lines at which the glass is of substantially uniform thickness, and terminating short of the edges of the sheet, which are ordinarily thicker than the body otthe sheet, so that the danger of breakage due to localized pressure is reduced, (4) which provides for gripping the sections of glass as produced in the device by the cutting operation so that each sheet or section is supported at one end independently of the other sections, thus reducing the strain imposed upon the sections, and which provides for the heating of the drawing devices prior to their engagement with the glass ribbon. One embodiment of the invention is illustrated in the accompanying drawings wherein: I

Figure 1 is a partial side elevation and partial section looking at one side of the apparatus; Fig. 2 is a partial section and partial front elevation at ri 'ht angles to the metal views of Fig. 1; Fig. 3 is a side elevation of the structural work and drive mechanism taken from the side opposite to that of F 1; Fig. l is a plan view of the apparatus of Fig. 3; Fig. 5 is a detail side elevation of the shields employed on the outer sides oi the drawing belts;,Fig. 6 is a partial vertical section on an enlarged scale through the inner flights of thedrawing belts; Fig.

'7 is an enlarged transverse section through one end of the drawing belt construction;

of a modified belt construction.

The drawing mechanism which constitutes the subject matter of the present application is illustrated in Figs. 1 and 2 in connection with the annealing chamber of my application Serial No. l98,212 through which the glass is drawn preliminary to its engagement by the drawing belts, such annealing chamber comprising a vertical movable section A which may be adjusted up and down inside the section B, such section A lying above the drawing pot C which carries a bath of molten glass. The pot C lies in a heating chamber D and glass is supplied to the pot from the melting tank E. The sections A and B of the annealing chamber are preferably heated by means of electricity and by means of suitable gas burners F, which heating means, however, constitute no part of the present invention, being described and claimed in my pending application heretofore referred to.

Thedrawing mechanism, to which the present application is directed, comprises the pair of endless belts G and H which extend upwardly from the leer section B a distance of approximately 7 5 feet, such dimension being subject to modification depending upon conditions. The drawing belts are made up of chains with transverse panels therebetween and extend around suitable sprockets I and J at their upper ends as indicated in Fig. 3 which sprockets are driven from the electric motor K. In their upward movement the opposing fiights of the two belt-s between which the glass is gripped are guided between the angle guides L and M (Fig. 3), While at their lower ends, the belts, which are of the roller type, are guided by the castings N and O.

In order to heat the flights of the belts preliminary to their engagement with the glass, the shields P and Q (Fig. 1) are employed, such shields being spaced away from the belts so as to provide heating chambers to which heat is supplied from the upper section D of the annealing chamber. In initiating the drawing operation a suitable bait is lowered between the drawing belts Q and H, such belts being run backward to permit of this lowering operation, and after the glass in the bath has adhered or is otherwise attached to such bait, it is drawn upward through the belts, and as soon as the glass reaches these belts, it is gripped therebetween and during the fur ther operation, the drawing function is accomplished by the belts, the bait being cut away from the glass either during its progress through the belts or after it emerges from the upper end thereof.

The construction of the drawing belts will be best seen by reference to Figs. 6 to 10 in connection with Figs. 1 and 3 which show the location of the guide channels for the chains at the edges of the belts. The chains are made up of side bars 1-1 and 22 carrying at their pivots 3 the rollers l with U shaped members 5 secured to the side bars intermediate the rollers by means of the bolts 6. Extending transversely between the chains are the metal panels 7, U shaped in cross section (Fig. 6) and secured at their ends to the members 5 of the chains by means of the bolts 8 (Fig. Extending around the face of each of the panels is a sheet of asbestos 9, such sheets being extended back between the flanges of the panels as indicated at 10 in Fig. 6 and secured together at 11 by rivets or other suitable securing means. The side edges of the sheets are held yieldingly in contact by means of metal plates 12 (Fig. 7) carried upon the stems 13 pressed forward by the springs 14. The stems 13 extend through the panels 7 and are guided at their outer ends in the clips 15 riveted to the flanges of the panels. In this manner a tight contact is insured along the edges of the belts and any access of draft to the glass between the belts is prevented.

fit suitable intervals along the belts, preferably about (5 feet apart, suitable gripping means are provided for engaging the glass sheet 16, such gripping means being formed by the use of strips of asbestos board 17, placed intermediate the faces of the metal panels 7 and the asbestos fabric 9, as indicated in Figs. 6 and 7. These boards terminate short of the side edges 18, of the glass sheet so that no pressure is applied to such edges. In the ordinary production of sheet glass a thick edge 18 results somewhat as indicated in Fig. 7 and it is desirable to avoid gripping such edges as this would involve the application of the gripping force to a comparatively small area, as it is much safer to apply this gripping force to a larger area such as is involved in providing the boards or strips 17 extending nearly across the width of the sheet being drawn.

In order to permit of the severing of the glass sheet or ribbon into sections while still en the drawing belts, slots are provided immediately above each pair of gripping strips as indicated in Fig. 6. These slots are closer. when not in use by means of the metal stripsl9 held in place by the catches 20.. These catches are pivoted on the rivets 21 with their ends formed so as to hook around other rivets 22 carried by the plates 19, the other ends of the catches being held releasably in position by means of the thumb screws 23. Vv hen the sheet arrives at the cutting point, the plate 19 is removed and a cutting tool is run across the sheet, this be ing accomplished either by a hand tool or a suitable auton'iatic mechanism. The plate 19 is then replaced, the apparatus moving continuously ahead during this cutting off operation. This cutting operation is preferably carried out at the point at which the sheet has lost sullicient heat so that it may be readily cut. This operation during the progress of the ass through the belts reduces the danger of breakage, as the length of the ribbon subject to pressure is reduced and in case of breakage after the cutting point is passed, the breakage is restricted to the single length of glass; whereas, the crack or break might be prolonged indefinitely through a continuous sheet. In this wa-y the glass is cut into suitable lengths and e ch length is suspended independently at its upper edge and the strain imposed upon the sheet tending to break it is reduced to a minimum.

The belts are also preferabiy provided with means whereby the speed of cooling of the sheet of glass passing therethrough may be regulated. It is desirable that the speed of cooling increase as the sheet progresses upward between the belts and that the cooling be relatively slow during the first part of the travel of the sheet as this slow cool ing in the initial portion of the draw insures better annealing and less breakage. At the later stages of the operation rapidity of cooling has no effect upon breakage or upon the quality of the glass with respect to strain, and during this period very rapid cooling may occur, and is desirable, in order to speed up the ope ation and give a minimum temperature to permit of ready handling when the sections of the sheet emerge from the belts. The variation in the rapidity of cooling as the sheet progresses upllli) Ill] ward is preferably accomplished by the use of a shielding device back of each of the belts which has an increasing heat transmitting capacity from the lower to the upper portions of the belt. This is preferably accomplished by making the shield of de creasing thickness, asbestos board or some other materialof this general character being employed in the composition of the shield, although the invention is not limited to the use of any particular means for accomplishing the decreasing insulating function. The shields decreasing in thickness at the backs of the belts are illustrated in Fig. 6 in which 24, and 26indicate shield sections or decreasing thickness from the lower to the upper portions of the belt. These shields may be supported from the angles L and M by means of the brackets 2'? and the sp ces at the ends thereof closed by means of angle clips 28 fitting into the panels and riveted thereto, as indicated in' Fig. 7. At the extreme upper ends of the belts, the shield sections may be entirely dispensed with and the heat transmittingcapacity of the panels themselves may be increased throughout by reducing the thickness of the asbestos fabric 9 or entirely omitting such fabric, in which case the shields at the backs of the panels would be so constructed as to give the desired heat insulating effect, the invention contemplating broadly the use of panels, either with or without an insulating covering on the face thereof, as shown in Figs. 11, 12 and 13 and later described, in connection with the shields at the backs of the panels where-- by the heat dissipating capacity of the belts may be decreased as rapidly or as slowly as may be found necessary or desirable.

In order that the gripping devices carried by the panels of the belt may exercise a yielding pressure upon the sheet. of glass and thus avoid danger of breaking the glass in case the glass is not perfectly flat, provi sion is made for supporting one or both of the guide angles L and M yieldingly. It is necessary to support only one of these guides yieldingly, and this is the construction illus trated, although the invention is not limited to providing yieldingsupport for one guide angle. In the device as constructed, the angle or track L, which is the one toward the tank, is yieldingly mounted, while the other track or angle M is rigidly supported from the structural framework made up of the commercial sections 29, 30, 31, 32, etc., the method of supporting the track or angle L being shown most clearly in Figs. 1 and 3.

As here shown the angle L is provided with clips 33 to which are pivoted the levers 34, provided at their outer ends with the counterweights 35 and hung from the transverse beams 29, 30, 31, etc. by means of the hangers 36. By regulating the position of the shoes N and 0 (Fig. 3), the two shoes for each side being connected by means of the transversely extending angle bars and 40. The upper ends of the shoes are yieldingly held outward by means of the bars 41 and a2, pivoted at their inner ends to the shoes and carrying the coil springs a3 and l i lying between the outer sides of the beams 32 and suitable adjusting nuts carried by the ends of the rods. This arrangement provides the necessary give due to varying thicknesses of glass and to expansion and contraction incident to varying heat conditions. I In order to provide for the heating of theflights of the belts before they come in contact with the glass and to give them a temperature approximately that of the glass so that it may not be unduly chilled, heating devices are provided extending upwardly from the lower ends of the belts along the outer flights, such devices comprising shields spaced away from the surfaces of the belts and with the space between the shields and the lower ends of the belts in communication with the annealing chamber below the belts A circulation of heated air is thus provided upward between the belts and the shields which gives the belts the desired increase in temperature before engaging the glass sheet. The shields P and Q are shown in detail in Fig. 5 and comprise sheet metal plates at; suitably supported by angles 47 and hung at their upper ends from the transverse frame members 31 by means of the links 48. The links 48 are provided with angle iron shoes 49 which have their inner flanges against the inner faces of the rolls l of the belt chains. These shoes are pivoted at 50 to the links 51, and such links 51 are held yieldingly outward by means of the levers 52 pivotally supported upon the frame mem bers 32 and carrying at their outer ends the counterweights 53.. In this manner the up per ends of the shields P and Q, are maintained in fixed relation to the belts since the counterwei hts hold the shoes 49' at all times against the inner faces of the belt chains. This takes care of any changes in the position of the belt incident to expansion or contraction or other causes which might 1 upward between the shields and the belts from the chamber B gives the added extra temperature to the belts which is necessary, but this might be augmented, if desired, by additional heater means, such as, burners applied to the space between the belts and the shields.

Means for driving the belts at the desired speed is shown in Figs. 3 and l, the drive being accomplished from the electric motor K, mounted upon the. floor which is preferably provided at the extreme upper ends of the drawing belts. The sprockets I and J are mounted upon the axles 57 and 58, such a: l being provided with worm wheels which are engaged by worms in the casings 59 and 60. The shafts of these worms are provided with spur gears (31 and 62, which are driven from the gears and 64 carried by the counter-shaft (55. The countershaft driven from the motor K through the intermediary of the belt 66 and the reducing mechanism in the casing 67. This gives the desired speed reduction, although it will be understood that the invention is not limited to any particular motor drive or speed reduction.

Figs. 11, 12 and 123 illustrate a modified form of belt construction, heretofore referred to, and involving the omission of the asbestos sheets 9 employed in the belt construction of Figs. 6 and 7. ihis omission of the asbestos sheeting involves a cheapen- 'ing of the construction and reduction in the cost of upkeep. The severe conditions of use including the relatively high temperatures to which the belts are exposed causes the asbestos to deteriorate in the course of time and its replacement is a matter of coin siderable expense and delay. The emission of the asbestos has the further advantage that in the upper stages of the belts, where it is desirable to speed up the cooling of the glass, this can be done more rapidly in the type of construction in which the insulating effect of the asbestos is absent.

In this construction of Figs. 11, 12 and 13, 68 are the panels U shape in cross section as in the other form of belts. At intervals are the gripping devices comprising the asbestos boards 69 surrounded by the asbestos sheets 70 to give a more yielding gripping surface for the glass sheet 71, the boards being held in position by the rivets 72. The extreme ends of the panels are secured to the chain links 73 having the rollers 73 and guides 7-1 as in the other con struction. Cutting slots are provided just above the gripping devices (Fig. 11), such slots being closed by the doors 75 hinged at 76 and held in closed position by the pivoted latches 77. Back of the belts are the shield or heat retainers 78 supported on metal plates 7 9 and decreasing in heat retaining capacity from the bottom up as in the construction of Fig. 6. The ends of the spaces between the panels and shields are closed by the clips 80 secured to the panels, while the spaces between the opposing panels have their ends closed by the over-lapping angle plates 81 and 82 secured to the panels as indicated in Fig. 13. These plates have their ends formed as indicated at 83 in Fig. 12, so as to still overlap as the panels progress around the ends of the device.

In order to make tighter joints between the adjacent panels, the alternate sides are preferably extended and bent at right angles as indicated at Sa in Figs. 11 and 12.

.Vhat I claim is:

1. A drawing device for sheet glass comprising a pair of opposing endless belts for gripp'ng the sheet therebetween, and means for driving the be ts, one of the said belts being provided at intervals with transverse slots to permit the cutting of the glass while passing along between the belts.

9. A drawing device for sheet glass com prising a pair of opposing endless belts for receiving the glass therebetween and gripping means at intervals along the belts, in opposition to each other and moving with the belts, the belts also being provided above the gripping devices with transverse slots to permit the cutting of the glass while passing along between the belts.

3. A drawing d vice for sheet glass comprising a pair of opposing endless belts for gripping the sheet therebetween, one of which is provided at intervals with transverse slots to permit the cutting of the glass while passing along between the belts, covers for said slots, and means for driving the belts.

A drawing device for sheet glass com-- prising a pair of endless belts and means for driving the belts, said belts each comprising chains, transverse metal panels secured thereto and placed edge to edge so as to provide a substantially continuous surface, and insulating means covering the front faces of the panels.

5. A drawing device for sheet glass comprising a pair of endless belts and means for driving the belts, said belts each comprising chains, transverse metal panels secured thereto and placed edge to edge so as to provide a substantially continuous surface, and insulating means covering the front faces of the panels and extending between the edges of said panels.

6. A drawing device for sheet glass comprising a pair of endless belts and means for driving the belts, said belts each comprising chains, transverse metal panels U shape in cross section secured thereto, and an insulating fabric covering the front faces of the panels and extending between their edges.

7. A drawing device for sheet glass comprising a pair of opposing endless belts,

means for driving the belts, opposing rigid gripping means carried by the belts at spaced intervals along the length thereof and movable therewith, and guide ways along the edges of the belts for said gripping means, the said gripping means having glass engaging surfaces of yielding material of less length than the width of the sheet of glass draw-n, so that the edges of the sheet are not engaged by said surfaces.

8. A drawing device for sheet glass comprising a pair of endlessbelts, said belts made up of roller chains, and transverse metal panels secured to thechains and having their faces covered with an insulating material and placed edge to edge so as to provide a substantially continuous surface, guides for the rollers, and neans for driving the belts;

9. A drawing device for sheet glass comprising a pair of endless belts each consisting of a pair of chains, transverse metal panels secured to the chains, sheets of insulating material covering the inner faces of the panels and extending ou past the edges of the glass sheet to be drawn, and means for yleldlngly pressing together the edges of the opposing sheets of insulating material lying outside otthe edges of the glass sheet.

10. A drawing device for sheet glass comprising a pair of endless belts each consisting of a pair of chains, transverse metal panels secured to the chains, sheets of insulating material covering the inner faces of the panels and extending out past the edges of the glass-sheet to be drawn and means carried by the panels for yieldingly pressing together the edges of the opposing sheets of insulating material lying outside of the edges of the glass sheet.

11. A drawing device for sheet glass comprising a pair of opposing endless belts for gripping the sheet therebetween, means for driving the belts, and heating means extending along the belts in advance of their engagement with the glass.

12. A. drawing device for sheet glass comprising a pair of opposing endless bolts for gripping the sheet therebetween, means for driving the belts, and a heating chamber extending along each of the belts in advance of their engagement with the glass.

13. A drawing device for sheet glass comprising a pair of opposing vertical endless belts for gripping the glass therebetween, means for driving the belts, heat retaining walls opposite the lower outer side of each of the belts, and means for applying heat to the lower ends of the spaces between said walls and the faces of the belts whereby the belts may be heated preliminary to their engagement with the glass sheet.

14. A pair of endless belts for drawing sheet glass comprising a pair of chains for each belt, transverse opposing gripping members carried by the chains, guides for the chains and means for yieldingly press ing the guides for one belt toward the guides for the other belt, so that one set of gripping members is yieldingly supported in op position to the other set.

15. A pair of endless belts for drawing sheet glass comprising a pair of chains for each belt, transverse opposing gripping members carried by the chains, a pair or fixed guides for one of the pairs of chains, a pair of guides for the other pair of chains mounted for movement toward and from the fixed guides, and means for yieldingly holding the movable guides in their advanced positions.

In testimony whereof, I have hereunto subscribed my name this 10th day of October, 1922.

HALBERT 1;. HITGHGOCK. 

